People view the 3-dimensional (3D) physical world without any particular discomfort. However, viewing stereoscopic displays frequently causes complaints of visual discomfort, including symptoms closely resembling motion sickness.
Visual discomfort symptoms such as eye strain, blurred vision, and double vision may be related to fundamental limitations of stereoscopic 3D (S3D) display technology that result in oculomotor conflict between accommodation and convergence demands, a difference between viewing distance to the screen (focal distance), and the distance to the virtual stereo images (convergence distance). Lack of naturally-occurring blur at different virtual distances may also result in visual discomfort. Studies of 3D visual discomfort with stereo displays have suggested that 2D image distortions during capture (e.g., lens distortion) and projection distortions of the scene (e.g., keystone distortion) cause localized misalignment between the left and right eye images, especially in the periphery. These distortions disrupt natural stereo fusion, and may increase overall 3D viewing discomfort.